How to Outsmart a Bug
It’s harder than you might think to outsmart a bug. I’ve spent the last 27 years trying to keep wildlife healthy by outsmarting the pathogens, or bugs, that cause disease. Sometimes it works, sometimes it doesn’t. But when it works, it is awesome because preventing disease is always better than treating it.
We recently took up the challenge of preventing some potentially deadly blood parasite infections in our birds at the Safari Park. These parasites are transmitted by biting insects, so if we want to prevent disease we have to find a way to stop the mosquitos and midges responsible for transmission. The task becomes more challenging when you consider the constraints we have to deal with: it can’t involve broadcasting toxic pesticides (because we don’t want to harm the beneficial bugs at the Park or the other species that feed on them), and it can’t involve treating the birds with drugs to prevent infection (even if we had effective drugs, it would be too risky and stressful for the birds).
In order to outsmart the bugs, we have to understand their life cycles and feeding strategies, then identify the most effective points of intervention. With generous funding from the Ellen Browning Scripps Foundation, we set out on an ambitious study to document the diversity, abundance, and distribution of biting insects in several key locations at the Safari Park, to document the pathogenic parasites they carry, and to identify the various animal hosts they are feeding on. This would allow us to map out their preferred habitats and hosts, and then find the vulnerable points for intervention.
This project has been challenging - requiring a diverse array of expertise and a lot of work, but it also has yielded some interesting results and provided great experiences for our summer student interns.
Over the course of a year we collected nearly 10,000 individual insects representing 13 different species of mosquitoes and midges. Who would’ve thought there were so many different species of these biting insects here in San Diego! About 40% of the samples from insects that had taken a blood meal were positive for avian hemoparasites, revealing high potential for transmission events.
Interestingly, these bugs had fed on 52 different species of hosts, most of them native wild mammals roaming the Park (including humans). The next steps will be to look more carefully at the spatial distribution of these mosquitoes and midges around the Park, focusing on the species that carry hemoparasites and prefer avian hosts.
Much more analysis awaits us, but I’m growing increasingly confident that we are going to outsmart the bugs this time. And it is going to be awesome when we do.
Bruce A. Rideout, D.V.M., Ph.D., D.A.C.V.P.
Director, Wildlife Disease Laboratories